This invention relates to new chemical compounds useful as intermediates for the preparation of compounds having valuable pharmaceutical properties. The invention particularly relates to a steroselective reductive alkylation process for the preparation of novel asymmetric N-substituted amino acid derivative intermediates useful in the preparation of Angiotensin Converting Enzyme Inhibitor (ACEI) compounds.
Syntheses with asymmetric induction have been known in the prior art. A synthesis with asymmetric induction is commonly defined as a process in which a chiral unit in an ensemble of substrate molecules induces, by a reaction with achiral units, resulting molecules in such a manner that the stereoisomeric products are produced in unequal amounts. Such an asymmetric synthesis may be of great economic value for excluding or reducing the amount of unwanted isomers when only one of the diastereomers is of use or interest.
The reactants used in an asymmetric synthesis can be at least one chiral component consisting of a chemical reagent, solvent, catalyst or an energy such as circularily polarized light. Alternatively, by selection of specific enantiomers as starting compounds, the preferred stereoisomer in predominant amount can be induced.
An object of the present invention is to provide asymmetric N-substituted amino acid derivatives in which the (S,S) diastereomeric compound predominates.
Another object of the present invention is to provide a process for synthesizing asymmetric N-substituted amino acid derivatives which process is simple utilizing readily available starting materials, economical, and which can be conveniently scaled up to industrial scale production.